NEXT GENERATION SEQUENCING FOR IDENTIFICATION OF RESISTANCE-ASSOCIATED SUBSTITUTIONS IN HEPATITIS C DIRECT-ACTING ANTIVIRALS TREATMENT FAILURES

Yael Gozlan ¹ Avia Rakovsky ¹ Rachel Shirazi ¹ Ziv Ben-Ari ^2,3 Ella Mendelson ^1,4 Orna Mor ¹

¹Central Virology Laboratory, Ministry of Health, Ramat-Gan
²Liver Disease Center, Chaim Sheba Medical Center, Ramat-Gan
³The Sackler School of Medicine, Tel Aviv University, Tel Aviv
⁴School of Public Health, Tel Aviv University, Tel Aviv

Background: Treatment of HCV with the new direct acting antivirals (DDAs) is highly successful (>90%). However, resistance-associated substitutions (RASs) in the NS3/4A protease (NS3), the replication factor NS5A and viral NS5B polymerase might emerge and compromise treatment success. Recent international guidelines (EASL and AASLD), recommend resistance-mutation testing prior to re-treatment. Here, we assessed the utility of next generation sequencing (NGS) compared to ABI based sequencing (ABS) for the detection of resistance associated mutations in such DAAs treatment failures.

Methods: Blood samples from 24 patients failing new DAAs treatment regimens were collected. The NS3, NS5A and NS5B HCV regions were amplified and assessed by both ABS and NGS (MiSeq, Illumina). DeepChek-HCV software (ABL) was used for interpretation of all sequencing results.

Results: Analysis of 92% of the samples (22/24, 2/24 were not assessed yet) revealed that 68% (14/22) exhibited one or more NS3 (Q80K, D168V) and/or NS5A (L31M, Y93H) post-treatment ABS- detected RASs; Q80K was detected in 4.5% (1/22) of the patients, D168V was detected in 18% (4/22) of the patients, L31M in 18% (4/22) and Y93H in 59% (13/22). Other patients (41%, 10/24) had no ABS-detected RASs. Results of the NGS analysis and comparison between ABS and NGS mutation profile will be presented.

Conclusions: Major RASs were identified in the majority of DAA treatment failures. The added value of NGS will be discussed.